The present invention relates to a method of testing the abnormality of the interval timer of a personal computer, and more particularly to such a PC (personal computer) interval timer test method, which achieves the test by comparing the periodic interrupt frequency of the PC""s CMOS R.T.C (Real Time Clock) with the interrupt frequency of the PC""s interval timer within the same time period.
Conventionally inspecting the abnormality of the interval timer of a PC is achieved simply by comparing the PC""s interval timer with its internal CMOS R.T.C. The precision of this test method can reach only the unit of seconds. There is another interval timer test method of testing the abnormality of the interval timer of a PC by using an oscilloscope. However, when an oscilloscope is used, the casing of the computer to be tested must be removed. Therefore, this interval timer test method is complicated.
It is one object of the present invention to provide a PC interval timer test method, which achieves high precision. It is another object of the present invention to provide a PC interval timer test method, which enables the test to be run without removing the casing of the computer. According to the present invention, the test is achieved by: calculating the difference between the periodic interrupt frequency of the PC""s CMOS Real Timer Clock with the interval timer interrupt frequency within the same time period, and then judging the result by comparing the value of the difference thus obtained with the set maximum allowable value of error of the CMOS R.T.C""s periodic interrupt frequency. Because the maximum frequency of a CMOS RealTime Clock can be as high as 8192 Hz, the test error can be as minor as below 1/8192.